just because someone has an oscar doesn't make them "less" of a fish keeper then someone that has a red devil or other extremely large aggressive fish. My husband and I have been in this hobby for over 15 years and used to have many absolutely huge fish. We have had a 31" arrowana, a 28" clown knife, a 26" marble sailfin catfish, a huge male midas with huge nuchial hump, a 30" tiger shovelnose cat, a 12" male bifasciatus, very large tiger datnoids, a 28" fire eel that we used to handfeed ghost shrimp, etc. I was simply looking for a good suggestion as to what to possibly put in with this oscar that happens to be much more aggressive then the typical oscar especially as his small size. Thank you all for the suggestions, they are much appreciated!